Couplers and attachment assemblies are used to couple panels to one or more support members such as bars, brackets, and braces. For example, in motor vehicles, a plurality of panels and support members support and couple an instrument panel to a vehicle body. In particular, instrument panel support structures are often constructed from stamped and welded steel sheet metal assemblies and may include a plurality of supporting brackets or braces having a sufficient amount of surface area to allow the support structure to be attached to the vehicle and the instruments and other devices to be securely fastened within the panel.